Electric discharge device for space resonant circuits



July 27, 1948. J. E. BEGGs 2,445,992 ELECTRIC DISCHARGE DEVICE FOR SPACE RBSONANT CIRCUITS rma sept. 1o, 194s l Inventor: James BBe s,

Hs Attorney.

Patented July 27, 1948 ELECTRIC DISCHARGE DEVICE FOR SPACE RESONANT CIRCUITS James E; Boggs, Scotia, N. Y., assigner to General Electric Company, a corporation of New York Application September 10, 1943, SeriaiNo. 501,799

22 Claims.

My invention relates to electric discharge devices suitable for low or high frequency applications and, more particularly, to space-resonant systems of the high frequency type using such devices.

It is an object of my invention to provide new and improved electric discharge devices.

It is another object of my invention to provide new and improved electric discharge devices suitable for operation in the ultra-high frequency region.

It is another object of my invention to provide new and improved forms of ultra-high frequency electric discharge devices suitable for use in space-resonant cavities.

Briefly stated, in accordance with one of the illustrated embodiments of my invention, I provide a new and improved electric discharge device suitable for use in low frequency or space-resonant systems and comprising a pair of cylindrical electrodes surrounded by a concentrically spaced cylindrical metallic' structure hermetically sealed at its opposite ends to the electrodes to form therewith adjacent sections of a concentric transmission line. When used in an ultrahigh frequency system these sections form at least a part of space-resonant cavities, an electrcde supported from the metallic structure defining boundaries of the pair of space-resonant or tuned cavities. These cavities are connected to external or utilization circuits through auxiliary or tuning regions or cavities which may be adjusted in their characteristics to establish with the portions of the cavities within the hermetically sealed region conditions of resonance, thereby affording means for controlling or adjusting the characteristics of the energy supplied to the utilization circuits.

Another feature of my invention is a vacuumtight glass window particularly adapted for use in conjunction with centimeter wave devices, the glass window being hermetically sealed to a metal housing which may be soldered to an opening in the high frequency device, the window serving to seal adjacent sections of the device having differential pressures therebetween or to facilitate observation of operations within said high Irequency devices. Accordingly, it is another bject of my invention to provide an improved window glass particularly adapted for inclusion in centimeter wave devices.

Still another feature of my invention is a sealing arrangement for coaxial or concentric transmission lines in which a glass seal may be easily inserted between sections of the concentric transmission line having differential pressures therebetween, the glass having a temperature coeillclent of expansion substantially equal to that of the metalic conductors of the transmission line and having a low high-frequency dielectric-loss. The glass is hermetically sealed to the inner conductor of the concentric transmission line and to' a tubular metallic sleeve having an outwardly directed ilange which may be easily soldered to the transmission line. Alternatively, the arrangement may be used in fabricating electric discharge tubes, a pair of such sleeves being placed in opposed relation, the short sections of the inner conductors functioning as electrodes of the discharge device and the glass seals serving as means to support its principal electrodes, while the flanges of the metal tubes serve to support a desired arrangement of control electrodes between the principal electrodes. It is a further object of my invention, therefore, to provide a new and improved arrangement for fabricating electric discharge devices.

It is still another object of lmy invention to provide a new and improved structure for an electric discharge device which is adapted for insertion in e concentric or coaxial transmission line.

For a better understanding of my invention, reference may be had t'o the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims. Fig. 1 diagrammatically illustrates an embodiment of my invention as applied to a glass Window for sealing adjacent sections of a high frequency energy transmission system; Fig. 2 diagrammatically illustrates an embodiment of my invention as applied to an electric discharge device of the diode type; Fig. 3 dagrammatically illustrates another embodiment of my invention as applied to an electric discharge device of the triode type and used in a broadcast frequency circuit; Fig. 4 represents a further modification of my invention as applied to a space-resonant discharge device and system; and Fig. 5 is another modification of my invention as applied to an alternative method of fabricating an electric discharge dev-ice.

Referring to Fig. 1, my invention is there illustrated as applied to a wave guide system of the metallic hollow pipe type. The wave guide I comprises two adjacent sections 2 and 3 which may be operating under dierent pressure conditions. Thus, the hollow pipe I may be illled with'a gas under pressure, while the hollow pipe 2 may be nlled with air at atmospheric pressure.

The hollow pipes 2 and 3 may be formed from copperor silver-plated iron. for example.

In order to permit continuous transfer of energy along the wave guide I, I provide a metallic tube 4 of copperor silver-plated iron and having a configuration similar to that`of the hollow pipes 2, 3 and disposed within and in metallic contact with the inner wall of pipe 2. The tube 4 has an inwardly directed ange 5 at its upper end and an outwardly directed flange B at its lower end. The hollow pipe 3 has a similar flange portion 'I overlying the ange 6 and hermetically sealed thereto, as by soldering or brazing. Alternatively a rubber gasket and a suitable clamping arrangement may be used to seal the nanges 6, 1. The pipe 2 may be similarly sealed to the opposite side of flange 6. Hermetically sealed across the inwardly directed flange 6 is a glass window 8, the glass of said window having a low high-frequency dielectric-loss and a temperature coelcient of expansion substantially equal to that of the copperor silver-plated iron. One glass particularly suited for this purpose contains about 45 per cent SiOz, 14 per cent KnO, 6 per cent NazO, 30 per cent PbO, and `5 per cent CaFz.

'I'he vacuum-tight glass window shown in Fig. 1 is particularly useful in an ultra-high frequency transmission system, either for the .passage of high frequency currents therethrough without the introduction of any serious or undesirable reflections, or for observations of elements, such as a spark gap or electric discharge device which may be mounted within an ultra-high frequency system. In constructing the window, a piece of flat glass 8 may be placed across the flange I5 and may be heated indirectly by applying heat to the metallic member 4 Ibyvany suitable means, such as high frequency induction, the glass wetting very easily and effectively with the copperor silver-plating on the iron member 4.

Referring -to Fig. 2, I have shown an improved ultra-high frequency electric discharge device in the construction of which the principles of the metal-to-glass sealing arrangement shown in Fig. 1 are applied. The discharge device Il! shown in Fig. 2 comprises a substantially cylindrically anode II and a substantially cylindrical cathode I2, these two electrodes `being coaxially aligned and having their adjacent ends in spaced opposed relation. The anode II may be a hollow or a solid copperor silver-plated iron cylinder,

while the cathode I2 comprises a hollow copperor silver-plated iron tube I3 to the upper 'end of which is attached, as by welding, a thin sleeve I4 of Fernico foil. The Fernico sleeve is provided at its upper end with an inwardly directed flange I5 and a disk I6 of any suitable electron emitting material, such as nickel coated with barium and strontium carbonates, is welded to the flange I5. A tubular eyelet I8 is attached to the under surface of disk I6 and surrounds a heating element or filament I9. In this construction, the fernico foil I4, because of its low thermal conductivity, functions to provide thermal isolation of the cathode disk I6 from the iron tube I3, while the eyelet I8, composed of a good thermal conducting material, such as nickel, serves to conduct heat radiated outwardly from lament I9 to disk I6.

A pair of transversely extending glass insulating disks 20, 2I are hermetically sealed, respectively, to the anode III and the cathode II at intermediate points on their length. A pair of metal tubes 22. 23 are hermetically sealed, respectively, to the disks 20, 2i conceutrically to surround the anode and cathode. 'The tubes,

ically sealed together, -as by soldering or welding, to form with the `disks 20, 2| a closed region surrounding at least apart of the anode II and.A

cathode I2. The cathode structure I2 is provided with a small hole 28 in its portion lying within the above-mentioned closed region, which serves as means for gettering" the tube, in a manner to be pointed out later, to reduce the gas pressure within the enclosed region.

In constructing the electric discharge device illustrated in Fig. 2, the anode II and the metal tube 22 are held in concentric positions in a press. A ring of glass 20 is placed in position and the elements are heated to the flowing temperature of the glass, after which a suitable tubular press (notfshown) passing along the outer side of the anode I I engages the glass ring causing it to form a hermetic seal between the anode II and the tube 22. Thereafter the unitary structure is annealed and cooled in the usual manner. A similar method of fabricating the cathode structure is employed. Thereafter, the flanges 25 and 28 are placed together with a ring of solder between them. 'Ihe tube is evacuated in a bell Jar to obtain a minimum gas pressure in the regionsurrounding the electrodes. The solder ring may be then heated indirectly to its wetting point by hi'gh frequency induction currents or by applying an excess voltage to filament I9.to heat the composite cathode structure to a temperature where the solder melts and seals the junction between the flanges 25, 26. In order to provide still lower gas pressure within the discharge device III, a getter may be enclosed within the tubular cathode I2 and ashed by means of electric currents further to lower the gas pressure within the discharge device.

The electric discharge device thus illustrated in Fig. 2 is simply and easily fabricated. Moreover, any desired type of electric discharge device may be manufactured by including one or more grids or control electrodes between the opposed flanges 25, 26. An electric discharge device of the triode type so fabricated is shown in Fig. 3 wherein a metal ring or washer 30 having a central opening across which is supported a grid 3| of fine wires is clamped between the flanges 25, 26. By this structure, the -grid is supported between the anode II and the cathode I2 in'spaced relation with their opposed ends.

In the structure outlined, for ultra-high frequency applications, the anode I I forms with the tube 22 a short section of concentric or coaxial transmission line. Similarly, the cathode II2 and the tube Riformrasecond short section of transmission line. YSucii'a section of transmission line may function as a portion of a space-resonantor tuned cavity, the electrodes of the discharge device dening boundaries for the .pair of spaceresonant or tunedcavities associated with the anode-grid and grid-cathode circuits. g

The electric discharge device illustrated in Fig. 3 is also particularly adapted for use in low frequency circuits such as employed in -radio broadcasting and reception, i. e., in wired circuits rather than space-resonant circuits. An important feature of its construction is the very low inductance of its anode, grid, and cathode leads, the inductances of these leads being of a value considerably lower than that which exists in radio tubes of the conventional type. A circuit suitable for use with the electric discharge device as an oscillator comprises an inductance Il connected` between anode II and a metallic sleeve 3|, closely spaced about tube 22 and insulated therefrom by means of a layer of suitable insulation l2, such as mica, to form therewith a by-pass capacitor connected between inductance 30 and grid 3I. A similar sleeve 33 and layer of insulation 34 surround tube 23 to form therewith a by-pass capacitor serially connected with inductance 33 between cathode I2 and grid 3l. Where required a cathode resistance 33 may be connected between the upper extremity of sleeve 33 and ground. Current for heating mament I3 may be supplied by a source of alternating voltage 31 connected between the upper extremity of sleeve 33 and a conductor 32, connected to one terminal of thel filament, through an inductance or choke coil 39 the other terminal being connected to tube I3. Operating potential for anode II may be supplied from a suitable source, indicated by the legend B+, over a conductor 3l connected to the lower extremity of sleeve 3|. In the oscillatory circuit, coils 3.3 and 35j are coupled capacitively through sleeves 3|, 22 Aand 33, 23 as well as the interelectrode capacitance. They may also be coupled additionally in any well-known manner as operating conditions require.

In Fig. 4, I have shown how means external to the electric discharge device may cooperate therewith to constitute one or more tunable spaceresonant cavities. The electric discharge device shown in this figure is of the tetrode type having rst and second grids or control electrodes 33, 34 supported respectively from metal rings or washers 35, 33, the rings being insulated from each other by means of a layer of insulating material 31 and being clamped between the opposed flanges of the metal tubes 22, 23. In order that the tubes 22, 23 may be electrically isolated from each other in this form of the electric discharge device, they are hermetically sealed by means of a. glass bead 33. The discharge device thus shown comprises two tuned resonant cavities or regions, one of which is the grid 33-anode cavity which is defined between the longitudinal surface of the anode II and the interior surface of the metal tube 22, and the other of which' is the grid 34-cathode cavity or region defined by the longitudinal surface of the cathode I2 and the-inner surface of the metal tube 23. In both cavities it is, of course, understood that the resultant or overall natural frequency of these cavities is determined by the auxiliary or tuning cavity now to be described.

I provide auxiliary or tuning space-resonant cavities which may be partially defined by conductive or metallic members, such as th'e pair of metallic cylinders 4I, 42 coaxlally surrounding, respectively, the anode II and the cathode I2 and electrically connected thereto by means of the cylindrical plungers 43, 44. The cylinder 4I is provided at its left-hand end with slotted lingers 45 surrounding the metal tube 22 and insulated therefrom for unidirectional currents by means of the tube 43 of a suitable insulating material, such as mica. The cylinder 42 is similarly provided with slotted ilngers 41 which surround the tubular ring 23, being insulated therefrom for unidirectional currents by means of the insulating tube 43. The cylindrical or annular plungers 43, 44, which are positionable or slidable along the inner surfaces of the cylinders 4|, 42 and the outer surfaces of the anode and cathode and being in close engagement with these surfaces in order to prevent the establishment of any discontinuities in the rconductive medium which defines the cavity, provide means in the spaceresonant system for tuning or controlling the natural resonant frequency of the system including the above-mentioned cathode-grid 34 cavity and the external cavity formed by cathode I2 and cylinder 42 and, likewise, the anode-grid 33 cavity and the external cavity formed by anode II and cylinder 4I. The plungers 43, 44 may be positioned by any suitable mechanical expedient, such' as the adjusting knobs III, II, and energy may be injected in or extracted from the space-resonant regions by any suitable input or output means which are shown in Fig. 4 as the conductive loops 52, 53 forming a part of coaxial transmission lines comprising, respectively, outer conductor I4 and inner conductor 55 and outer conductor 33 and inner conductor 51.

In Fig. 4, I have likewise shown in greater detail the construction of the cathode I2, in particular the sealing arrangement for this cathode and the location of the getter 30. The twov ends of the getter are connected to a pair of conductors CI, 62 which are embedded in a glass seal supported in a metallic sleeve 83. The filament I3 is connected between conductor 32 and sleeve 33, which sleeve is hermetically sealed, as by soldering, to the inner surface of the tubular cathode I2.

Upon the impressing of a suitable unidirectional potential across the anode II and the cathode I2, high frequency electromagnetic energy may be delivered to the space-resonant system through the transmission line comprising conductors 56, 51 and derived from the space-resonant system through the transmission line comprising conductors 54, 55. Operation or adjustment of the plunger 44 controls the tuning of the space-resonant cavity defined by the cathode I2, the control electrode 34, the metal tube 23, and the cylinder 42. When the electric discharge device is used for amplifying energy, this space-resonant cavity is adjusted to resonate at the frequency of the input energy. Similarly, operation or adjustment of the plunger 43 controls the intensity or magnitude of the high frequency electromagnetic energy within the space-resonant cavity defined by anode II, grid 33, metal tube 22, and cylinder 4I, this magnitude being greatest when this cavity is tuned to resonate at the same frequency as the cathode-grid 34 cavity.

When the space-resonant system is used as a high frequency oscillator, it may be considered that coupling between the anode-grid 33 cavity and the grid-cathode 44 cavity or region is obtained by the mutual capacitances of the opposing surfaces of the anode II and the cathode I2 so that the energy may be fed back by the anodegrid cavity to the grid-cathode cavity, maintaining the system at the frequency of operation. The intensity or magnitude of the high frequency electromagnetic oscillations wthin the space-resonant system may be controlled by adjustment of the plungers 43, 44 which determine the natural resonant frequencies of the regions defined by the cylinders 4I, 42 and the anode-grid cavity and grid-cathode cavity of the discharge device.

Fig. 5 shows an alternative arrangement of an electric discharge device of the triode type applicable to either low or ultra-high frequencies and which embodies further features of my invention. The portions of the discharge device shown in Fig. 5, which are similar to those shown in the other figures, have been assigned like reference numerals. In the Iarrangement of Fig. 5, I provide an auxiliary anode structure in the form of a solid metal cylinder 1I attached to the anode tube il and having a diameter smaller than that of the hollow anode tube Il. A composite cathode structure similar to that shown in detail in Fig. 4 has its emissive disk I6 in opposed relation tothe adjacent end of anode 10, the diameter of disk I6 being substantially equal to the diameter of anode 10. The tube i3, whose outer diameter is equal to the diameter of anode Il, has an inwardly flanged portion I3. The metal ring 30 which supports the grid 3| is soldered between a pair of metallic rings 13;: 14. Cylindrical insulating members 15, 16, preferablyformed of glass of the type previously mentioned, surround the auxiliary anode and the adjacent end of the cathode, respectively, and are hermetically sealed at one of their ends to the metallic members Il and I3' and at their adjacent ends to the rings or plates 13, 14. The cylindrical insulators 15, 16 are of such length that the anode and cathode project into the central apertur in the metal plates 13,` 14 and invspaced relation with each other and with the grid 3|. The anode and cathode cylinders Il, I2 and the rings 13. 14 preferably are formed of silveror copper-plated iron so that a good hermetic seal is obtained between the metal and the glass cylinders 15, 16, the glass of these cylindershaving a temperature coefficient of expansion substantially equal to that of the iron tubes to which it is connected and a low high-frequency dielectric-loss. The diameters of the opposed electrodes I6, 10, and the spacing between these electrodes, are determined by the particular operating characteristic desired for the electric discharge device so constructed, The same consideration holds with respect to the diameters of the electrodes shown in the othergures. For this reason, referring to Fig. 4, the anode is shown as having a bevelled edge at its left-hand end and the cathode structure, at its right-hand end, as being reduced in size from the size at the left-hand end. With reference again to Fig. 5, when the electric discharge device there depictedis to be used' for ultrahigh frequency purposes, metal cylinders correspending to the metal cylinders 4i, 42 shown in Fig. 4 may be placed varound the anode Il and the cathode i2 and connected to the plates 13,.

14 for high frequency conduction. In this way, the anode and cathode structures of the discharge device function as inner conductors of sections of concentric transmission line serving as space-resonant devices. Since the control electrode 3l is clamped between and conductively connected to the plates 13, 14, these plates provide means whereby biasing potential may be supplied to this electrode.

Although, in the above described embodiments of my invention, I have chosen to represent a space-resonant system as applied only to the devices shown in Fig. 4, it is readily apparent that` improved electric discharge devices. such as those depicted in the other gures, may likewise be used in conjunction with such space-resonant systems and that they may be employed either as an; oscillator or for other purposes, such as amplifiers, converters, and the like.

- Furthermore, while in the above descriptive` matter certain of the devices have been described as high frequency electric discharge devices. it is apparent thatgthe structures shown willoperate equally as well at low frequencies as pointed out in the case of the discharge device of Fig. 3. My invention, therefore, provides an improved electric discharge device which may be employed either as an ultra-high. frequency electric discharge device or as a device operating at low trequencies. The improved` tube structure of my invention. moreover. is one which not only ,is easily fabricated, but by which tube structures for all purposes and with any number of electrodes may be constructed simply and with improved accuracy. Since the cathode and anode project from opposite ends as cylinders, while the grid structure is centrally located and connected to a metallic cylinder of larger diameter from that of the anode and cathode, the" electric discharge devices have low inductance leads which are suitable for 4low frequency applications and are adapted forluse in end-to-end concentric transmission line space-resonant systems. the electrode forming portions of the conductors of such a transmission line While I have shown and described my invention as applied to particular systems embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modifications may be made without departing from my invention and I, therefore, aim in the appended claims to cover all such changes and modiiications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by' Letters Patent of the United States is:

1. A high frequency electron discharge device comprising a'pair of cylindrical and substantially coaxially aligned electrodes, a tubular metallic said structure and forming therewith sealed portions of cavity resonators'connected respectively between said electrodes and said control member.- said electrodes extending through said dielectric members in opposite directions and providing externally accessible terminals for said electrodes.

y2. A high frequency electron discharge device comprising a pair of cylindrical and substantially coaxially aligned electrodes, tubular metallic means concentrically surrounding saidelectrodes forming therewith a section oi' concentric transmission llne, a control member interposed between said electrodes and coupled to said tubular metallic means, dielectric means hermetically sealed between saidelectrodes and said tubular means forming a sealed portion of a cavity resonator connected between each of said electrodes and said control member, said electrodes extending through said dielectric means in opposite dlrections and providing externally accessible terminals for said electrodes, and a metal structure coupled with said metallic means external to said sealed portions for completing said cavity resonators. i

3. An electronic discharge device of the sealed envelope type, comprising a cylindrical electrode. a transversely extending insulating disk hermetically sealed to said electrodey at a point spaced longitudinally from the end thereof, said electrode extending through said disk and providing an externally accessible terminal, a metallic cylinder hermetically sealed to said disk and concentrically surrounding said end of said electrode defining therewith a portion of a concentric transmission .line, said cylinderand said disk defining a part ot said sealed envelope, and means hermetically sealed to said cylinder Lsupporting a complementary electrode in opposed spaced relation with said end of said iirst electrode.

4. An electronic discharge device of the sealed envelope type comprising a substantially cylindrical electrode, a transversely extending insulating disk hermetically sealed to said electrode at a point spaced from one end thereof, said electrode extending through said disk and providing an externally accessible terminal, a metallic cylinder concentrically surrounding the portion of said electrode between said disk and said end and hermetically sealed to said disk forming with said portion of said electrode a section of a concentric transmission line, a second electrode, means supporting said second electrode in spaced relation with said end and forming with said first named electrode and said cylinder the envelope of said device.

5. An electronic discharge device comprising a pair of substantially coaxial and cylindrical electrodes having their adjacent ends in spaced opposed relation, a pair of transversely extending insulating disks hermetically sealed respectively to said electrodes at intermediate points thereof, a metallic cylindrical structure surrounding said electrodes and hermetically sealed to said disks deiining a closed region about a portion of said electrodes, a control member interposed between said electrodes and coupled with said metallic cylinder, said cylindrical structure and said electrodes forming a pair of short sections of concentric transmission lines connected respectively between said control member and said electrodes.

6. An electric discharge device comprising a cylindrical anode, a cylindrical cathode substantially coaxially aligned with sald anode, said anode and said cathode having their adjacent ends in closely spaced relation, a ilrst tubular metallic sleeve concentrically surrounding said anode and extending therealong forming therewith a section of concentric transmission line, a second tubular metallic sleeveconcentrically surrounding said cathode and extending therealong forming therewith a second section of concentric transmission line, said sleeves having opposed anges at their adjacent ends joined in sealing relation, and insulating means hermetically sealed respectively between said anode and said first sleeve at its other end and between said cathode and said second sleeve at its other end, said electrodesextending through the respective insulating means providing externally accessible terminals.

7. An electric discharge device comprising a cylindrical anode, a cylindrical cathode substantially coaxially aligned with said anode, said anode and said cathode havingtheir adjacent ends in closely spaced relation, a iirst tubular metallic sleeve concentrlcally surrounding said anode and extending therealong forming therewith a section of concentric transmission line, a second tubular metallic sleeve concentrically surrounding said cathode and extending therealong forming therewith a. second section of concentric transmission line, said sleeves having opposed ilanges at their adjacent ends joined in sealing re1ation,` and glass insulators hermetically sealed respectively between sald anode and said rst sleeve at its other end and between said cathode and said second sleeve at its other end, said electrodes extending through said insulators in opposite directions and providing with the respective one of said sleeves externally accessible terminals for said sections of transmission line.

8. An electronic discharge device comprising, a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, a metallic cylinder concentrically surrounding said anode and cathode and hermetically sealed to said discs. and means conductively connected to said cylinder supporting a grid between said anode and cathode in spaced relation with said opposed ends.

9. An electronic discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxlally aligned therewith and having its end in opposed spaced relation with the adjacent end of said anode, a pair of tubular metallic members surrounding said anode and cathode respectively, glass discs hermetically sealed between the remote ends of said members and said anode and cathode respectively supporting said anode and cathode in coaxial alignment with said members, said cathode and anode having portions extending through said discs providing externally accessible terminals therefor, said members having hermetically sealed opposed flanges at their adjacent ends, and a grid disposed between said anode and cathode and supported from said iianges.

10. An electric discharge device comprising, a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end oi' said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, a pair of metallic cylinders concentrically surrounding said anode and said cathode respectively and hermetically sealed to the respective disc thereof, a metallic ring supporting a grid between said anode and cathode in spaced relation with said opposed ends, said cylinders having hermetically sealed opposed iianges, and said ring being supported between said opposed flanges.

11. A high frequency space resonant system including a high frequency electronic discharge device comprising, a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end ot said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and sald cathode at intermediate points thereof, tubular metallic means concentrically surrounding said anode and cathode and hermetically sealed to said discs and forming a closed region, said anode and said cathode extending irom opposite ends of said closed region, means conductively connected to said tubular means and supporting a grid between said anode and cathode in spaced relation between said opposed ends, and means external to said discharge device and comprising a pair of conductive members connected between said tubular means and said anode and said cathode respectively and constituting with said anode and cathode a part of the cavity resonators formed therewith.

12. A high frequency space resonant system including an electric discharge device compristially cylindrical cathode coaxially alignedtherewith and having its end in opposed spaced relationl with the adiacent end oi' said anode, a pair of tubular metallic members surrounding said anode and cathode respectively. Blass discs hermetically sealedbetween the remote ends of said members and between said anode and cath ode supporting said anode and cathode in coaxial alignment with said members, said cathode and anode having portions extending through said discs providing accessible terminals therefor, said members having hermetically sealed opposed flanges at their adjacent ends, la grid disposed between said anode and cathode and supported from said ilanges, and means external to said discharge device and comprising a pair of conducting members connected respectively between said anode and its associated oneoi' said members and between said cathode and its associated one of said members and constituting therewith a part of a pair of cavity resonators, and adjustable means movable within said members for controlling the natural frequencies of said resonators. y

13. A high frequency space resonant system -including an electric discharge device comprising a substantially cylindrical anode, a substantially vcylindrical cathode coaxially aligned therewith and having-its end in opposed spaced relation with the adjacent end of said anode, a pair of tubular metallic members surrounding said anode and cathode respectively, glass discs hermetically sealed between the remote ends oi' saidv members and between said anode and cathode supporting said anode and cathode. in .coaxial alignment with 'saidA members, said cathode and anode having portions extending through said discs providing externally accessible terminals therefor, said members having hermetically sealed opposed flanges at their adjacent ends, a grid disposed between said anode and cathode and supported from said flanges, and means external to said discharge device and comprising a conductive member connected to said anode and constituting therewith a part of a cavity resonator.

14. A high frequency space resonant system including an electric discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having its end in opposed spaced relation with the adjacent end of said anode, a pair of tubular metallic members surrounding said anode and cathode respectively, glass discs hermetically sealed between theremote ends of said members and between said anode and cathode supporting said anode and cathode in coaxial augment with said members, said cathode and anode having portions extending through said discs providing externally accessible terminals therefor, said members having hermetically sealed opposed ilanges at their adjacent ends, a grid disposed between said anode and cathode and supported from said ilanges, means external to said discharge device and comprising a conductive member connected to said anode and constituting therewith a part of a cavity resonator, and means for controlling the natural frequency of said cavity resonator.

l5. A high frequency space resonant system in,-

i 12v ot transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, metallic cylindrical means concentrically surrounding said anode and said cathode and hermetically sealed to said discs forming a sealed region enclosing a POrtion oi' said anode and said cathode. means conductively connected to said cylindrical means supporting a grid between said anode and cathode in spaced relation with said 1 opposed ends, and means external to said discharge device land comprising a metallic tubular member connected to said metallic cylindrical means and in concentric spaced relation with the portion of said anode external of said region constituting with said anode and said grid a space resonant cavity.

16. A high frequency space resonant system including an electric discharge device comprising asubstantially cylindrical anode, a. substantially cylindrical cathode coaxially aligned therewith and having one of its ends infopposed spaced relation with the adjacent endof said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, a pair of metallic vcylinders concentrically surrounding said anode'and said cathode respectivecluding an electric discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, apair ly and hermetically sealed to the respective discs thereof, said cylinders having hermetically sealed opposed flanges and forming with said discs a sealed region enclosing a portion of said cathode and said anode, a grid supported from said flanges between said anode and cathode in spaced rela,-

tion with said ends, and means external to saidl discharge device and comprising a plurality of tubular members concentrically spaced respectively with said anode and said cathode constituting therewith a plurality of cavity resonators.

17. A high frequency space resonant system including an electric discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, a

pair of metallic cylinders concentrically surrounding said anode and said cathode respective- 1y hermetically sealed to the respective discs thereof, said cylinders having hermetically sealed opposed flanges and forming with said discs a sealed region enclosing a portion of said cathode and said anode, a grid supported from said flanges between said anode and cathode in spaced relation with said respective end, means external to said discharge device and comprising a plurality of tubular members concentrically spaced respectively with said anode and said cathode constituting therewith a plurality of cavity -resonators, and adjustable means in said members for controlling the natural frequencies of said resonators.

18. An electronic discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith l pair of metallic cylinders surrounding said anode and said cathode respectively and hermetically sealed .to the disc thereof, a plurality of metallic rings supporting respective grids between said anode and cathode in spaced relation with each other and with said opposed ends, said cylinders having hermetically sealed opposed flanges, said rings being supported between said opposed flanges and being insulated from each other and conductively connected to the adjacent one of said flanges.

19. An oscillator comprising an electronic discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one oi' its ends in opposed spaced relation with 4the adjacent end of said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, a pair of metallic cylinders surrounding said anode and said cathode respectively and hermetically sealed to the respective disk, a grid disposed between said anode and cathode and condnctively connected .to said cylinders, a pair of metallic sleeves surrounding said cylinders and insulated therefrom forming therewith a plurality of capacitances, arr inductance serially connected between said anode and the one of said capacitances, and an inductance serially connected between said cathode and the capacitance associated therewith.

20. .An electronic discharge device comprising a cylindrical anode, a cylindrical cathode substantially coaxially aligned therewith, and a control electrode in spaced relation bet-Ween adjacent ends of said anode and cathode, a metallic sleeve concentrically surrounding said anode and cathode and conductively connected to said control electrode, insulating means hermetically sealed between said anode and cathode respectively and said sleeve defining therewith a sealed envelope, the portions of said cathode and anode external of said envelope providing terminals therefor, and said sleeve providing an externally accessible terminal for said control electrode.

21. A high frequency electronic discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation with the adjacent end of said anode, a .pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode at intermediate points thereof, a pair of metallic cylinders surrounding said anode and said cathode respectively and hermetically sealed to the disc thereof, a plurality of metallic rings supporting respective grids between said anode and cathode in spaced relation with each other and with said opposed ends, -said cylinders having hermetically sealed opposed flanges, said rings being supported between said opposed flanges and being insulated from each other and conductiveiy connected to the adjacent one of said flanges, said cylinders and said discs forming a sealed region enclosing portions of said anode and said cathode and said grids. and means external to said discharge device and comprising a pair of tubular members concentrically spaced respectively with the portions of said anode and said cathode external of said region constituting with the respective electrodes a pair of cavity resonators. f

22. A high frequency electronic discharge device comprising a substantially cylindrical anode, a substantially cylindrical cathode coaxially aligned therewith and having one of its ends in opposed spaced relation -with .the adjacent end of said anode, a pair of transversely extending insulating discs hermetically sealed respectively to said anode and said cathode atintermediate points thereof, a pair of metallic cylinders surrounding said anode and said cathode respectively and hermetically sealed to the disc thereo, a plurality of metallic rings supporting respective grids between said anodeand cathode in spaced relation `with each other and with said opposed ends, said cylinders having hermetically sealed opposed flanges, said rings being supported between said opposed flanges and being insulated from each other and conductively connected to the adjacent one of said flanges, said cylinders and said discs forming a sealed region enclosing portion-s of said anode and said cathode and said g'rids'means external to said discharge device and comprising a pair of tubular members concentri.

cally spaced respectively with the portions of said anode and said cathode external of said region constituting with the respective electrodes a pair of cavity resonators, and means in said members for controlling the natural frequencies of said resonators. I

JAMES E. BEGGS.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date v1,304,868 Franklin May 27, 1919 1,407,061 Gray Feb. 21, 1922 2,125,280 Bieling Aug. 2, 1938 2,153,131 Bohme Apr. 4, 1939 2,153,728 Southworth Apr. 11, 1939 2,167,201 Dallenbach July 25, 1989 2,314,794 Linder Mar. 23, 1943 2,333,295 Chevigny Nov. 2, 1943 2,351,744 Chevigny June 20, 1944 Certilcatel of Correction'- Patent No. 2,445,992. July 27, 1948.

JAMES E. BEGGS It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correctlon as follows:

Column 2, line 5, after the Word ,high strike out the hyphen; line 6, after the syllable tric strike out the hyphen; column 3, line 20, after high" strike out the hyphen; same line, after dielectrlc strike out the hyphen; column 6, line 60, for wthin read within; column 8, lines 16 and 17, for electrode read electrodes; line 53, claim 2, after means 'first occurrence strike out the comme; column 11, line 12,

claim 12, after providing insert externally;

and that the said Letters Pate'ntshould be readwith these corrections therein that the same may conform to the record of the case 1n the Patent Office. v

Signed and sealed this 8th day of Februery,-A. D. 1949.

THOMAS F. MURPHY, I f Assistant Gommz'asoner of Patents. 

